JP4575170B2 - Solenoid valve - Google Patents

Description

  The present invention relates to an electromagnetic valve according to the first part of claim 1.

  Proportionally operated electromagnetic valves are known in the art. Unlike conventional solenoid valves that operate in two positions, this proportionally operated solenoid valve does not operate in a pulsing manner and does not utilize the full structurally possible stroke of the valve closure member, thereby buffering the valve closure member. Show continuous movement. Consistently actuated proportionally, which is 'softly' adjusted in terms of control technology, contaminants collect in the area between the valve seat and the valve closing member, and in a given environment It cannot be excluded that the operation of both the system connected to the system is impaired. For example, DE 19653895 A1 describes an electromagnetic valve having a proportional type structure.

  In view of the foregoing, it is an object of the present invention to improve a generally proportionally operated solenoid valve that eliminates the above disadvantages while maintaining the simplest possible design.

According to the present invention, the object is an electromagnetic valve for a wheel slip control system of an automobile, in which a valve closing member is movably guided, and a valve coil attached to the valve housing. A magnetic armature that strokes in the direction of the magnetic core disposed in the valve housing to proportionally actuate the valve closing member in response to a control current supplied to the valve, and a valve that is not electromagnetically excited A spring for positioning a magnetic armature at a predetermined axial distance from the magnetic core in position and separating the magnetic armature from the magnetic core with a predetermined space, the valve coil comprising the control of the valve closing member This bar is actuated by current so that it strikes the valve seat with a predetermined impact force beyond the action proportional to the current. The current causing the valve closing member to collide with the valve seat is supplied to the valve coil when the fluid pressure acting on the valve closing member is minimum, and the contaminants attached to the valve seat and / or the valve closing member are removed. , Achieved by an electromagnetic valve that causes the valve closing member to pulse in a maximum stroke and collide with the valve seat .

  Other features, advantages and possible applications of the present invention are shown below by the description of one embodiment.

  FIG. 1 shows an overall view of a proportionally operable electromagnetic valve. Here, the electromagnetic valve is configured as a normally open two-way seat valve at its basic position, and the cartridge type valve housing 8 has a spherical valve closing member 9 on the stepped valve tappet 1. The valve tappet 1 contacts a cylindrical magnetic armature 10 at the opposite end of the valve closing member 9. The valve closing member 9 faces the tubular seat 2 and the magnetic armature 10 faces a magnetic core 11 incorporated in the valve housing 8. A sleeve that is preferably deep-drawn is attached to the magnetic core 11, and the magnetic armature 11 can be moved in axial alignment in the sleeve. A valve coil 13 is disposed on the outer periphery of the sleeve 12 and is embedded between a yoke-type plate member 16 and a magnet end plate 17.

  When the valve coil 13 is energized, the magnetic armature 10 moves in the direction of the magnetic core 11 in a manner known per se, and the valve closing member 9 formed on the valve tappet 1 is connected to the valve tappet 1 and the valve seat. The pressure fluid connection between the pressure fluid inlet channel 14 and the pressure fluid outlet channel 15 which are open in the basic position, continuously against the biasing force of the valve spring 4 interposed between Decrease.

  In order to maintain proportional control, in this embodiment, it is necessary to determine a predetermined geometric dimension between the valve seat member 2 and the valve tappet 1. For this purpose, the valve closing member 9 of the valve tappet 1 preferably has a spherical outer shape with a diameter of 1.8 to 2.2 mm. This corresponds to a seal diameter with a valve seat of 0.9 to 1.1 mm. The angle of the valve seat is 120 degrees. Therefore, it is particularly important to maintain the above dimensions and the cleanliness of each member.

  The electromagnetic valve is provided as an inlet valve used in an automobile brake system with slip control. In its basic position, the valve closing member 9 is lifted from the valve seat member 2 by a valve spring 4 interposed between the valve tappet 1 and the valve seat member 2.

In this configuration, in order to reduce or avoid deposits on the valve seat 2 and the valve closing member 9, the valve coil so that the valve closing member 9 collides with the valve seat 2 with a sufficiently large impact force exceeding a proportional operation. A special feature is that 13 can be operated with current. For this purpose, it is necessary to determine the power of the current so that the valve closing member 9 operates in a pulse shape with its maximum stroke and collides with the valve seat 2 with a corresponding strength.

In order to remove the contaminants deposited on the valve closing member 9 and the valve seat 2, the power of the current depends on the degree of contamination, i.e. mainly on the influence of changes in pressure inside the valve. It is selected according to the amount. In order to remove deposits from the valve seat 2 and / or the valve closing member 9, sufficient current is passed through the valve coil 13 during non-proportional valve operation. This current causes the normally inactive valve closure member 9 to impact the valve seat 2 continuously or discontinuously with an impact force that removes deposits.

  This method is particularly effective when the fluid pressure acting on the valve closing member 9 is minimal, so that the valve closing member 9 impacts the valve seat 2 with the maximum stroke and maximum speed with the minimum hydraulic resistance. Thus, even the most stubborn deposits can be removed from the valve seat 2 and the valve closing member 9 and, if necessary, can be removed by repeating the above procedure several times.

  The removed deposit can be cleaned from the area of the valve seat 2 and the valve closing member 9 when the fluid pressure in the valve is maximum. In order to obtain an optimal cleaning effect, the valve closing member 9 is subsequently switched to a position that forms the maximum opening cross-sectional area of the valve.

  In order to remove deposits on the valve seat 2 and / or the valve closing member 9, the magnetic coil 13 is actuated with an impact force to remove deposits at the latest when a leak occurs in the closed position of the valve. . In order to detect valve leakage between the valve seat 2 and the valve closing member 9, means are provided for detecting fluid pressure upstream and downstream of the valve closing member 9 or the valve seat 2 in the closed position of the valve. . A change in pressure indicative of valve leakage can be derived from the measured hydraulic pressure. As measuring means, pressure sensors 6 are arranged upstream and downstream of the valve closing member 9, which drive the valve coil 13 in order to evaluate a pressure sensor signal representative of the change in the pressure of the valve closing member 9. Connected to the electronic control unit 20. One pressure model is stored in the electronic control unit 20 and allows a comparison between an acceptable pressure difference due to valve contamination and a nominal pressure. For this purpose, the control device 20 is provided with a suitable evaluation circuit.

  A tandem master cylinder is connected as a brake pressure generator 3 to the pressure fluid inlet channel 14 of the solenoid valve shown in FIG. The pressure fluid outlet channel 15 of the electromagnetic valve is connected to the wheel brake 5 at the height of the valve spring 4. Connected to this pressure fluid connection leading to the wheel brake 5 is an outlet valve 7 and a return conduit having a low pressure accumulator 18 and a pump 19 according to the return hydraulic pressure delivery principle. This return conduit is connected to the pressure fluid inlet channel 14. The hydraulic circuit shown is a basic feature and is a general description. It is possible to change.

  Based on the state in which the solenoid valve is initially fully opened as shown, the valve coil 13 is not electrically energized, the solenoid valve is operated in a proportional or analog manner programmed in the controller 20. Is basically activated during brake pressure control. Therefore, the electromagnetic valve finely forms a required valve cross-sectional area with various control currents for pressure measurement.

  According to the figure, the solenoid valve is inserted in a brake pressure conduit connecting the brake pressure generator 3 in the automotive brake system with slip control to the wheel brake 5, and therefore the pressure is detected by the pressure sensor 6. Instead, appropriate software can be used to detect valve leaks with a corresponding pressure model in the controller 20. This pressure model takes into account the change in pressure in the wheel brake 5 and the brake pressure generator 3 that changes due to valve leakage. In certain situations, the use of a pressure model can eliminate the need for a pressure sensor.

  A pressure model representing a pressure change in the wheel brake 5 is calculated according to a parameter related to the vehicle and a parameter related to the brake. Such parameters include data on vehicle deceleration, initial pressure in the brake pressure generator, brake pressure increase and brake pressure characteristics according to the deposits in the valve. This pressure model takes into account, for example, the increasing slope of the change in brake pressure, especially when there is deposits in the valve.

  So far, the invention has been described by way of an example of a proportionally operated electromagnetic valve that is opened in its basic position, but the description made herein is also applicable to a proportionally operable electromagnetic valve that is closed in its basic position. It is. Thus, the invention disclosed herein is also applicable to the outlet valve 7 shown in FIG.

The whole figure of the electromagnetic valve which can be operated proportionally.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Valve tappet, 2 ... Valve seat, 3 ... Brake pressure generator, 4 ... Valve spring, 5 ... Wheel brake, 6 ... Pressure sensor, 7 ... Outlet valve, 8 ... Valve housing, 9 ... Valve closing member, 10 ... Magnetic armature, 11 ... Magnetic core, 12 ... Sleeve, 13 ... Electromagnetic coil, 14 ... Pressure fluid inlet channel, 15 ... Pressure fluid outlet channel, 16 ... Yoke type thin plate, 17 ... Electromagnetic end face, 18 ... Low pressure accumulator, 19 ... Pump, 20 ... control device.

Claims (9)

An electromagnetic valve for an automobile wheel slip control system,
In order to actuate the valve closing member proportionally in response to a control current supplied to a valve housing in which the valve closing member is movably guided and a valve coil attached to the valve housing. A magnetic armature that performs a stroke motion in the direction of the magnetic core disposed therein, and a magnetic armature that is positioned at a predetermined axial distance from the magnetic core at a valve position that is not electromagnetically excited. from at a predetermined space; and a spring for separating,
The valve coil (13) is actuated with an electric current so as to collide with the valve seat (2) with a predetermined impact force beyond an operation proportional to the control current of the valve closing member (9) ,
The electric current causing the valve closing member to collide with the valve seat is supplied to the valve coil (13) when the fluid pressure during brake pressure control acting on the valve closing member (9) is minimum, and the valve seat (2) and An electromagnetic valve that causes the valve closing member to pulse in a maximum stroke and collide with the valve seat until contaminants attached to the valve closing member (9) are removed .   The solenoid valve according to claim 1, wherein the power of the electric current is set so that the closing member (9) operates at its maximum stroke and collides with the valve seat (2).   In order to remove contaminants attached to the valve seat (2) and / or the valve closing member (9), the power of the current can be adjusted to vary depending on the degree of contamination. Item 3. The electromagnetic valve according to Item 1 or 2. While the valve is not proportional to the control current, a current is passed through the valve coil (13), which causes deposits from the valve seat (2) and / or the valve closing member (9). to remove the electromagnetic valve of claim 1, the valve closure member (9), characterized in continuously or discontinuously colliding with the valve seat with a predetermined impact force (2). In order to wash away removed deposits from the valve seat (2) and / or the valve closing member (9) when the fluid pressure during the brake pressure control is maximum, the valve closing member (9) is the maximum opening of the valve. The electromagnetic valve according to claim 1 , which occupies a position to give a cross section. When the valve leakage that occurs at the position where the valve is closed occurs, the valve coil (13) so as to form an impact force to remove the valve seat (2) and / or deposits of the valve closure member (9) The electromagnetic valve according to claim 1 , wherein the electromagnetic valve is operated. In order to detect the leakage of the valve between the valve seat (2) and the valve closing member (9), the fluid pressure upstream and downstream of the valve closing member (9) is measured at the position where the valve is closed. 7. The electromagnetic valve according to claim 6 , wherein means are provided. In order to detect pressure changes indicative of leakage of the valve , pressure sensors are arranged upstream and downstream of the valve closing member, which sensors evaluate pressure sensor signals representing pressure changes acting on the valve closing member. 8. The electromagnetic valve according to claim 7 , wherein the electromagnetic valve is connected to an electronic control device, the control device actuates a valve coil and has an evaluation circuit. In order to represent the change in hydraulic pressure acting on the valve closing member in the position where the valve is closed, the operating characteristic for one pressure model is stored in the electronic control unit, which is unacceptable due to valve contamination. electromagnetic valve according to claim 8 you comprising a pressure differential of, compared to the nominal pressure required for the detection of pressure changes.

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